The speed and processing power of mobile computing devices are escalating. The increased capabilities of mobile computing devices have enabled the devices to transition from textual displays to graphical displays and more recently to displaying multimedia such as streaming videos and mobile television. The ability to download and display multimedia on mobile communication devices necessitates a significant increase in wireless communication speeds for the mobile computing devices.
One way that wireless communication speeds have been increased is through the use of higher frequency bands, often greater than 2 GHz. The higher frequency bands allow for the use of a signal with wider bandwidth, thereby enabling faster wireless communication speeds. However, signals transmitted in the higher frequency bands also attenuate more quickly in the atmosphere and when traveling through buildings relative to lower frequency signals. The result of using higher frequencies is a smaller cell size and the need for more base stations. However base stations are relatively expensive to construct, operate. and maintain.
One way to reduce the costs of operating additional base stations is to introduce the use of low power base stations. Low power base stations can be used to communicate in areas where signals from traditional base stations have difficulty reaching, such as within buildings such as high rises, malls, hotels, homes, and other areas where significant potential interference may occur such as dense urban locations. Low power base stations have a number of names, such as micro cells, pico cells, and femto cells. Each of these cells are designed to provide an air link connection with mobile devices such as cellular phones and mobile computing devices, mobile internet devices, tablet computers, laptop computers, embedded communication devices in vehicles, and so forth. These mobile devices are commonly referred to as mobile stations.
As the number of deployed low power base stations increases, the potential for interference significantly increases between mobile phones communicating with a macro base station (i.e. a typical base station) and the signals emitted by a low power base station. Interference can be especially difficult when the macro base station and the low power base station each operate on the same frequency assignment.
For instance, a femto cell may be installed in a house to provide an increased coverage level in the house. As a person walks through his or her neighborhood, a connection between the person's cell phone and a macro base station may be overwhelmed by the signal transmitted by the femto cell located in a neighbor's house. This can cause the connection between the cell phone and the macro base station to significantly degrade or drop. Thus, the femto cell (low-power base station) can cause undesirable levels of interference in the communication between the cell phone and the macro base station.
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.